It already does that on mobile. It allows marking edges as connecting or not, and locking tiles with a long press.
I have an idea of placing them with some kind of gesture - like touch and drag between tiles. That wouldn't interfere with tapping to rotate tiles. But on the other hand, I'm usually zoomed in on mobile and I use touch and drag to move around. Interfering with that would be bad too.
I'm open to ideas for better controls.